scholarly journals Optimal Operation of Micro-grids Considering the Uncertainties of Demand and Renewable Energy Resources Generation

2016 ◽  
Vol 5 (3) ◽  
pp. 233-248 ◽  
Author(s):  
Malek Jasemi ◽  
Farid Adabi ◽  
Babak Mozafari ◽  
Samira Salahi

Nowadays, due to technical and economic reasons, the distributed generation (DG) units are widely connected to the low and medium voltage network and created a new structure called micro-grid. Renewable energies (especially wind and solar) based DGs are one of the most important generations units among DG units. Because of stochastic behavior of these resources, the optimum and safe management and operation of micro-grids has become one of the research priorities for researchers. So, in this study, the optimal operation of a typical micro-grid is investigated in order to maximize the penetration of renewable energy sources with the lowest operation cost with respect to the limitations for the load supply and the distributed generation resources. The understudy micro-grid consists of diesel generator, battery, wind turbines and photovoltaic panels. The objective function comprises of fuel cost, start-up cost, spinning reserve cost, power purchasing cost from the upstream grid and the sales revenue of the power to the upstream grid. In this paper, the uncertainties of demand, wind speed and solar radiation are considered and the optimization will be made by using the GAMS software and mixed integer planning method (MIP).Article History: Received May 21, 2016; Received in revised form July 11, 2016; Accepted October 15, 2016; Available onlineHow to Cite This Article: Jasemi, M.,  Adabi, F., Mozafari, B., and Salahi, S. (2016) Optimal Operation of Micro-grids Considering the Uncertainties of Demand and Renewable Energy Resources Generation, Int. Journal of Renewable Energy Development, 5(3),233-248.http://dx.doi.org/10.14710/ijred.5.3.233-248

: Due to the increase of load demand in future, the generation must also increase. The use of traditional resources such as coal, diesel fuels etc., causes global warming which is leading us to shift to renewable energy resources. Renewable energy resources may in include solar, wind, tidal as the source for production. These are used in small quantities as Distribution Generators (DG) at different locations in a bus system. As the generation of these sources is less when connected to grid, we call them as micro-grids. These micro grids generally use these DGs to distribute power to loads, and involve power electronic elements to control the generation. It induces energy into the system but also create a problem of harmonic distortions and voltage sags. To eliminate these sags and harmonics in the micro grid system caused by the power electronic devices employed by the renewable sources, we induce a UPQC (Unified Power Quality Conditioner) system. The UPQC system eliminates the harmonics in the systems and restores the voltage of the micro-grid system. We introduce a new topology called instantaneous reactive power (IRP) theory in the UPQC control to operate in a more efficient way, by utilizing RES (Renewable Energy Sources) at the DC-link. The RES support the UPQC system by injecting the active power generated by the resources through DC-link.


Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5482
Author(s):  
Shabir Ahmad ◽  
Israr Ullah ◽  
Faisal Jamil ◽  
DoHyeun Kim

Renewable energy sources are environmentally friendly and cost-efficient. However, the problem with these renewable resources is their heavy reliance on weather conditions. Thus, at times, these solutions are not guaranteed to meet the required demand all the time. For this, hybrid microgrids are introduced, which have a combination of both renewable energy sources and non-renewable energy resources. In this paper, a cost-efficient optimization algorithm is proposed that minimizes the use of non-renewable energy sources. It maximizes the use of renewable energy resources by meeting the demand for utility grids. Real data based on the load and demand of the utility grids in Italy is used, and a system that determines the optimal sizing of the microgrid and a daily plan is introduced to optimize the renewable resources operations. As part of the proposal, the objective function for the operation and planning of the microgrid in such a way to minimize cost is formulated. Moreover, a variant of the PSO algorithm named recurrent PSO is implemented. The recurrent PSO algorithm solves the proposed optimization objective function by minimizing the cost for the installation and working of the microgrid. Afterwards, the energy management system algorithm lays out a plan for the daily operation of the microgrid. The performance of the system is evaluated using different state-of-the-art optimization methods. The proposed work can help minimize the use of diesel generators, which not only saves financial resources but also contributes toward a green environment.


Electronics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 403
Author(s):  
Deyaa Ahmed ◽  
Mohamed Ebeed ◽  
Abdelfatah Ali ◽  
Ali S. Alghamdi ◽  
Salah Kamel

Optimal inclusion of a photovoltaic system and wind energy resources in electrical grids is a strenuous task due to the continuous variation of their output powers and stochastic nature. Thus, it is mandatory to consider the variations of the Renewable energy resources (RERs) for efficient energy management in the electric system. The aim of the paper is to solve the energy management of a micro-grid (MG) connected to the main power system considering the variations of load demand, photovoltaic (PV), and wind turbine (WT) under deterministic and probabilistic conditions. The energy management problem is solved using an efficient algorithm, namely equilibrium optimizer (EO), for a multi-objective function which includes cost minimization, voltage profile improvement, and voltage stability improvement. The simulation results reveal that the optimal installation of a grid-connected PV unit and WT can considerably reduce the total cost and enhance system performance. In addition to that, EO is superior to both whale optimization algorithm (WOA) and sine cosine algorithm (SCA) in terms of the reported objective function.


Electronics ◽  
2021 ◽  
Vol 10 (15) ◽  
pp. 1779
Author(s):  
Syed Rahman ◽  
Irfan Khan ◽  
Khaliqur Rahman ◽  
Sattam Al Otaibi ◽  
Hend I. Alkhammash ◽  
...  

This paper presents a novel, scalable, and modular multiport power electronic topology for the integration of multiple resources. This converter is not only scalable in terms of the integration of multiple renewable energy resources (RES) and storage devices (SDs) but is also scalable in terms of output ports. Multiple dc outputs of a converter are designed to serve as input to the stacking modules (SMs) of the modular multilevel converter (MMC). The proposed multiport converter is bidirectional in nature and superior in terms of functionality in a way that a modular universal converter is responsible for the integration of multiple RES/SDs and regulates multiple dc output ports for SMs of MMC. All input ports can be easily integrated (and controlled), and output ports also can be controlled independently in response to any load variations. An isolated active half-bridge converter with multiple secondaries acts as a central hub for power processing with multiple renewable energy resources that are integrated at the primary side. To verify the proposed converter, a detailed design of the converter-based system is presented along with the proposed control algorithm for managing power on the individual component level. Additionally, different modes of power management (emulating the availability/variability of renewable energy sources (RES)) are exhibited and analyzed here. Finally, detailed simulation results are presented in detail for the validation of the proposed concepts and design process.


Author(s):  
Baba Dzhabrailovich Babaev ◽  
Vladimir Panchenko ◽  
Valeriy Vladimirovich Kharchenko

The main objective of the work is to develop principles for the formation of the optimal composition of the energy complex from all the given power plants based on renewable energy sources for an autonomous consumer, taking into account the variable energy loads of the consumer, changing climatic conditions and the possibility of using local fuel and energy resources. As a result of solving this optimization problem, in addition to the optimal configuration of the power complex, it is also necessary to solve the problem of optimizing the joint operation of different types of power plants from the selected optimal configuration, that is, it is necessary to determine the optimal modes of operation of power plants and the optimal share of their participation in providing consumers at every moment in time. A numerical method for analyzing and optimizing the parameters and operating mode of the energy complex with the most accurate consideration of the schedule of changes in consumer load and software that automates the solution of this optimization problem are also presented.


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